1. Field of the Invention
The present invention relates to an ultrasonic motor in which an ultrasonic vibrator is pressed against a movable member with an anisotropic layer therebetween, whereby a force resulting from ultrasonic vibration generated in the ultrasonic vibrator is transmitted to the movable member by means of friction between the contact surfaces of the ultrasonic vibrator and the movable member to move the movable member.
2. Description of the Related Art
Basically, a movable member in an ultrasonic motor is moved by action of ultrasonic vibration generated in an ultrasonic vibrator. More specifically, every mass point of the ultrasonic vibrator in contact with the movable member repeats microscopic elliptical motion and the movable member strongly pressed against such ultrasonic vibrator is continuously driven by a friction force produced by action of the elliptical motion between the contact surfaces of the ultrasonic vibrator and the movable member.
Transmission efficiency of the driving force from the ultrasonic vibrator to the movable member is effected by various physical conditions. Such physical conditions include each modulus of elasticity of the ultrasonic vibrator and the movable member and the coefficient of friction on the contact surfaces.